One of the most common products of combustion encountered in structure fires is

• A. Benzene
• B. Carbon Monoxide
• C. Hydrogen Chloride
• D. Sulfur Dioxide

Answer: (B)

In structure fires, heat and often limited oxygen cause fuels to burn incompletely, and carbon monoxide is produced as a result. Carbon monoxide is especially dangerous because it is colorless and odorless, and it binds strongly to hemoglobin, forming carboxyhemoglobin, which severely reduces the blood’s ability to carry oxygen to tissues. This makes CO a widespread hazard across a wide range of burning materials, not tied to a single fuel. Other gases like hydrogen chloride, sulfur dioxide, or benzene can appear, but they depend on specific materials (such as chlorinated plastics or sulfur-containing fuels) and are not as universally produced as carbon monoxide.